Wireless battery management system, node for wireless communication, and method of transmitting data

1. A manager node comprising: a first wireless communication unit forming a primary channel based on a first frequency along with each of a plurality of monitor nodes collecting battery data; a second wireless communication unit forming a secondary channel based on a second frequency along with each of the plurality of monitor nodes; and a manager controller receiving battery data from each monitor node by using the first wireless communication unit, receiving battery data of a first monitor node by using the second wireless communication unit when communication by the first monitor node through the first wireless communication unit is impossible, and when communication by a second monitor node through the first and second wireless communication units is impossible, communicating with a third monitor node determined as a relay node by using the first wireless communication unit or the second wireless communication unit to receive battery data of the second monitor node from the third monitor node, wherein the manager controller measures a received signal strength of each monitor node by using the first wireless communication unit or the second wireless communication unit and selects a monitor node, where a level of the received signal strength is within a certain priority, as the relay node from among the plurality of monitor nodes.

2. The manager node of claim 1 , wherein the manager controller monitors communication quality of the primary channel, and when the communication quality is degraded as a result of the monitoring, the manager controller broadcasts channel change data, including identification information about a preliminary primary channel and identification information about a preliminary secondary channel, to each monitor node, changes the first frequency of the first wireless communication unit to a frequency of the preliminary primary channel, and changes the second frequency of the second wireless communication unit to a frequency of the preliminary secondary channel.

3. The manager node of claim 2 , wherein the manager controller measures an energy level of the first frequency to check an energy detection result value of the primary channel, measures a preamble of a frame occurring in the primary channel to check a frame measurement result value, checks a number of non-receptions representing a number of non-receptions of acknowledge (ACK) from each monitor node, respectively applies weight values to the energy detection result value, the frame measurement result value, and the number of non-receptions, summates a weight-applied energy detection result value, a weight-applied frame measurement result value, and a weight-applied number of non-receptions to calculate a degree of degradation of the primary channel, and when the calculated degree of degradation is outside a predetermined normal range, determines that the communication quality of the primary channel is degraded.

4. The manager node of claim 2 , wherein the manager controller searches for channels other than the primary channel to select a channel, where a preamble of a frame is not detected and an energy level of a frequency used thereby is lowest, as the preliminary primary channel from among the channels and to select a channel, where a preamble of a frame is not detected and an energy level of a frequency used thereby is lowest, as the preliminary secondary channel from among channels which are apart from the preliminary primary channel by a certain separation frequency.